“Doctor, I have a nodule in my thyroid, should I take medicine or have an operation?” Ultrasound is an important tool to detect nodules in the thyroid gland. The ultrasound has the first say in the disposition of the nodule, based on a series of ultrasound descriptions. This is the basis for the doctor’s initial determination of whether a particular thyroid nodule requires surgical treatment. It is more important for everyone who gets an ultrasound report to understand what the thyroid is telling them. Ultrasound descriptions of the number, shape, margins, size, calcification, and echogenicity of thyroid nodules are likely to raise questions in patients. In general, single nodules are most often seen in thyroid adenomas and thyroid cancer; multiple nodules are most often seen in nodular goiter and occasionally in multiple adenomas and multifocal malignancies. In terms of nodule morphology, oval and round nodules are more common and are usually benign, while a few are papillary thyroid cancer and follicular thyroid cancer; irregular nodules need to be alerted to the possibility of malignancy. In contrast, the incidence of malignant nodules with blurred borders is higher than that of benign nodules. The dynamic change in size is significant for the diagnosis of nodules, so regular follow-up of thyroid ultrasound is important. Patients are very anxious when they see the word “calcification” on the ultrasound report. In fact, calcification is divided into microcalcification, coarse calcification and marginal calcification. The former is mostly calcification and fibrosis secondary to amyloid deposits within the sand granules or medullary carcinoma, while the latter two are usually caused by malnutrition. Microcalcifications mostly appear as punctate strong echogenicity and are seen in 40-61% of papillary carcinomas. However, it can also be seen in other benign and malignant lesions. Coarse calcifications are mostly seen in benign nodules, especially nodular goiters. However, it can also be seen in some papillary thyroid carcinomas. Marginal calcifications are calcifications located at the margins of thyroid nodules and are commonly seen in nodular goiter, which is often a sign of a benign nodule. However, it is also seen in papillary and undifferentiated carcinomas. Normal echogenicity around the nodule is most often seen in thyroid adenomas and thyroid cancers. Abnormalities are most often seen in nodular goiter, which may show increased echogenicity, thickening, and unevenness. The specificity of very low echogenicity for the diagnosis of thyroid cancer is very high (92.2%-94.3%). Posterior echogenicity enhancement is most often seen in cystic nodules or benign thyroid lesions. Attenuation can be caused by large calcifications within the nodule or by the malignant nodule itself. Ultrasound examination of the peri-thyroidal and cervical lymph nodes is also necessary. Even in early stage papillary thyroid cancer, metastasis to the lymph nodes in the neck is very common. Even metastatic lymph nodes are detected before the primary focus. Therefore, in addition to detecting thyroid nodules, ultrasound is also an important tool to initially determine their benignity and malignancy. Today, ultrasound detection of thyroid nodules is becoming more and more frequent. Although the survival rate is high, there is still a 5%-15% cancer rate, so it should be taken seriously and health education interventions are especially important. Thyroid nodules often have no conscious symptoms and are mostly detected during physical examinations, so regular health checkups are the main way to detect thyroid nodules. Patients with thyroid nodules detected for the first time should remember to follow up regularly, usually once every 3-6 months, and then every 6-12 months depending on the actual situation. For those with high suspicion of malignant nodules, ultrasound-guided fine needle aspiration of the thyroid gland is feasible. Early detection of the lesion and identification of its benign and malignant nature is important for clinical treatment and surgical selection. As can be seen, some thyroid nodules can continue to be observed without treatment, and not all nodules need to be operated on.